ABSTRACT
BACKGROUND: Online pro-eating disorder (pro-ED) communities are considered harmful because of their detrimental effects on their users' body dissatisfaction, dieting, and help seeking. To date, it is unknown to which extent participation in pro-ED communities affects users' body weight and desired weight loss. OBJECTIVE: This study aims to investigate the changes in the current and desired body weight of users of a pro-ED community (r/proed) on the social media website Reddit over time. METHODS: Data on 1170 users and the unsolicited weight information they shared with the pro-ED community were collected over a period of 15 months. Linear growth models were used to model changes in the users' current and desired BMI over time. RESULTS: Both current and desired BMI decreased over time, with a predicted rate of 0.087 and 0.015 BMI points per week, respectively. Weight loss was moderated by the users' activity level in the community, with more active users losing more weight. Users with a higher baseline BMI experienced greater weight loss, but even users with a very low baseline weight (BMI <17 kg/m2) lost weight during their participation. In addition, users decreased their desired weight over time, with many pursuing extremely low, unrealistic weight goals. Changes in the desired weight were moderated by the baseline current BMI and baseline desired BMI. Users with higher desired weight and lower body weight at baseline decreased their desired weight more over time. CONCLUSIONS: This is the first study to demonstrate the detrimental effects of pro-ED communities in a longitudinal study based on a large data set of user-generated online data. The results extend the literature detailing the harmful effects of online pro-ED communities by showing users' weight loss, decreases in desired weight, and that higher activity levels lead to greater weight loss. Users could be driven to pursue very low, unrealistic weight loss goals by images of very thin bodies presented in these communities.
Subject(s)
Feeding and Eating Disorders , Social Media , Body Weight , Humans , Longitudinal Studies , Weight LossABSTRACT
Piecewise latent growth models (LGMs) for linear-linear processes have been well-documented and studied in recent years. However, in the latent growth modeling literature, advancements to other functional forms as well as to multiple changepoints or knots have been nearly non-existent. This manuscript deals with three extensions. The first is to a piecewise latent growth model incorporating higher-order polynomials. The second is to extend the basic framework to three phases. The last extension is to inherently nonlinear functions. In these extensions, the changepoint(s) is a parameter to be estimated and may be fixed or allowed to vary across subjects as an application warrants. The approaches are developed and two illustrative empirical examples from psychology are used to highlight the methodological nuances. Annotated statistical software is provided to make these elaborations accessible to practitioners and methodologists.
Subject(s)
Algorithms , Software , Humans , Models, StatisticalABSTRACT
Abstract Depression and stress have been related with poor Health Related Quality of Life (HRQoL) prognosis. However, it is not clear when these depressive symptoms should be measured. A sample of 177 Coronary Heart Disease patients were followed for 15 months aimed to compare the effect of depression and stress measure at time of hospitalization and three months later on the physical HRQoL trajectory. Linear growth models' results showed that depression and stress after discharge are negatively correlated with the physical HRQoL and depressive symptoms negatively affect the prognosis of these patients.
Resumo Depressão e estresse têm sido associados ao prognóstico da Qualidade de Vida Relacionada à Saúde (QVRS). Contudo, não há clareza sobre quando os sintomas de depressão devem ser mensurados. Uma amostra de 177 pacientes com cardiopatia isquêmica foi acompanhada por 15 meses, para comparar o efeito do estresse e a depressão durante a internação e, três meses depois, avaliou-se a trajetória do componente físico da QVRS. Os resultados da comparação de duas curvas de crescimento latente mostraram que a depressão e o estresse pós-alta estão negativamente correlacionados com o componente físico da QVRS, e que os sintomas depressivos afetam negativamente o prognóstico desses pacientes.
ABSTRACT
We investigated age-related differences in neuropsychological performance in 400 Indian school children (5-15 years of age). Functions of motor speed, attention, executive functions, visuospatial functions, comprehension, learning, and memory were examined. Growth curve analysis was performed. Different growth models fitted different cognitive functions. Neuropsychological task performance improved slowly between 5 and 7 years, moderately between 8 and 12 years and slowly between 13 and 15 years of age. The overall growth patterns of neuropsychological functions in Indian children have been discussed with the findings reported on American children. The present work describes non-linear, heterogeneous, and protracted age trends of neuropsychological functions in Indian children and adolescents.
